An image forming apparatus, constituted as a printer, photocopier, facsimile, or a multi-functional device with all of these functions, generally includes a changeable or recyclable processing unit, such as a toner cartridge or a process cartridge. For the processing unit, it is preferable to use a genuine product or a recommended product (licensed product of the manufacturer) supplied from the manufacturer of the image forming apparatus or a fabricant only in charge of production (hereinafter, they are both referred to as a manufacturer), the operation and performance of which is ensured by the manufacturer.
However, in recent years, unauthorized products are distributed to be used as the processing unit, the unauthorized products are not manufactured by the manufacturer of the image forming apparatus, and the operation and performance thereof are not guaranteed.
To avoid the problem of various defects due to the use of such an unauthorized product, Japanese Laid-Open Patent Application Tokukai 2003-39783 (published on Feb. 13, 2003) discloses a cartridge including an IC memory tag for storing information to distinguish the genuine product and recommended product from unauthorized product.
The image forming apparatus using the cartridge including an IC memory tag is capable of checking whether or not the processing unit is an unauthorized cartridge with an IC memory tag by reading out the information stored in the memory tag. Then, by informing the user of necessity of exchange of the cartridge with an IC memory tag, the use is protected from undesired use of unauthorized product.
However, some users prefer unauthorized products because of the low cost, even though they are aware of danger of possible defects.
When any defect is found in the product, the manufacturer is responsible for the damage according to the Product Liability (PL) Law (for chattels supplied through artificial operation or processing, such as industry products which are mass-produced and mass-consumed). However, if the trouble occurs with the use of unauthorized product, the manufacturer is not responsible for the damage, and may raise a dispute as to who is responsible for the loss caused by the defect.
For example, the manufacturers make efforts to reduce such a dispute as much as possible by warning the user non-guarantee of quality when the image forming apparatus is used with an unauthorized product, or supplying information of harmful condition inducing various defects, or inadequate use so as to ensure safe use of the apparatus. Therefore, the user of the image forming apparatus needs to confirm the warning or information given by the manufacturer so as to ensure the guarantee from the manufacturer. The warning or information may include the name of manufacturer of products, the date of manufacturing, or an identification of genuine product or recommended product.
The information display regarding product liability is generally given to the user in the form of a written notice attached to the main body of the product, the wrapping, or is written in the manual. However, fully understanding of given warning regarding use of the image forming apparatus is quite a trouble for the user; besides the confirmation is not possible if the medium containing the information is lost.
Moreover, many of image forming apparatuss have a function of estimating appropriate timing of exchange of the processing unit and informing the user of the estimation result, so that the user is able to change the unit at an appropriately timing. However, when an unauthorized product much lower in quality than a genuine product or a recommended product is used, it may decrease the life or function of the unauthorized product itself or other processing units mounted to the image forming apparatus.
Here, the estimation for exchange timing is made with assumption that the apparatus uses a genuine product or a recommended product, thus, when an unauthorized product is used, an appropriate exchange timing cannot be estimated. More specifically, because there is an error between the estimation result and actually-required exchange timing, a worn out processing unit may be continuously used without being exchanged, which may cause improper image forming or the like.